Channel tuner having two sets of rotatably mounted adjustable cams respectively controlling channel skipping and channel fine tuning



June 9, 1964 R. J. LINDEMAN ETAL 3, CHANNEL TUNER HAVING TWO SETS OFROTATABLY MOUNTED ADJUSTABLE CAMS RESPECTIVELY CONTROLLING CHANNELSKIPPING AND CHANNE L FINE TUNING Original Filed July 3, 1959 5Sheets-Sheet l INVENTORS.

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June 9, 1964 R. J. LINDEMAN ETAL 3,136,966

CHANNEL TUNER HAVING TWO SETS OF ROTATABLY MOUNTED ADJUSTABLE CAMSRESPECTIVELY CONTROLLING CHANNEL SKIPPING AND CHANNEL FINE TUNINGOriginal Filed July 5, 1959 5 Sheets-Sheet 2 IN VEN'I'ORS June 9, 1964 RJ. LINDEMAN ETAL RECEIVER 9 CHANNEL TUNER HAVING TWO SETS 0F ROTATABLYMOUNTED ADJUSTABLE CAMS RESPECTIVELY CONTROLLING CHANNEL SKIPPING ANDCHANNEL FINE TUNING Original Filed July 3, 1959 5 Sheets-S heet 3 MOTORTUNER REMOTE CONTRPL sauna? IN V EN TORS Bic/Lard J1 ind Qnz lw zgfjamwa,

June 1964 R. J. LINDEMAN ETAL 3,136,966

CHANNEL TUNER HAVING TWO SETS OF ROTATABLY MOUNTED ADJUSTABLE CAMSRESPECTIVELY CONTROLLING CHANNEL.

*SKIPPING AND CHANNEL FINE TUNING Original Filed July 3, 1959 5Sheets-Sheet 4 INVENTORS.

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June 9, 1964 R J. LINDEMAN ET 3,136,966 CHANNEL TUNER HAVING TWO SETS OFR TABLY MOUNTED ADJUSTABLE CAMS RESPECTIVELY CONTROLLING CHANNELSKIPPING AND CHANNEL FINE TUNING Original Filed July .3, 1959 5Sheets-Sheet 5 INVENTORS.

fickczrdlflindemm CZnZ'iwgyIlfam United States Patent CHANNEL TUNERHAVING TWO SETS OF ROTAT- ABLY MOUNTED ADJUSTABLE CAMS RESPEC- TIVELYCONTROLLING CHANNEL SKIPPING AND CHANNEL FINE TUNING Richard J.Lindeman, Elmwood Park, and Anthony T.

Monaco, Skokie, Ill.,assigners to Motorola, Inc, Chieago, 111., acorporation of Illinois Original application July 3, 1959, Ser. No.824,862, now Patent No. 3,069,638, dated Dec. 18, 1962; 'Divided andthis application Sept. 26, 1962, Ser. No. 226,413

5 Claims. (Cl. 334-21) This invention relates generally to tuners fortelevision receivers, and more particularly to a television tuningdevice for manual and/ or automatic channel selection with fine tuningwhich may be preset, and which tuning device may provide ultra highfrequency tuning as well as very high frequency tuning. This applicationis a division of our copending application Serial No. 824,862, filedJuly 3, 1959, and assigned to the assignee of the present application,now Patent No. 3,069,638. in Tuners for television receivers usuallyinclude a rotary channel selector switch having, twelve positionscorresponding "to channels in the very high frequency (VHF) band and aposition for use in receiving channels in the ultra high frequency (UHF)band. The channel selector includes waters which have circuit componentsmounted thereon and switch contacts for selectively connecting thecomponents. This forms a relatively complex structure which must becarefully constructed and which therefore is quite expensive.

Such tuners generally have a fine tuning device which makes it possibleto accurately tune the individual VHF channels as they are selected. TheVHF channels are in two separate spaced frequencybands and fine tuningdevices which operate to provide the required tuning range in one bandmay not provide adequate range in the other band. Also, it is generallynecessary to adjust the fine tuning each time a different VHF channel isselected,

, because the prior fine tuning adjustment when carried over to the newchannel is not the best setting for the new channel. to a centerposition and must therefore be set for the new channel.

It is desirable, therefore, to. provide a fine tuning device whichcontrols each channel independently of the others so that the viewer canpreset the fine tuning to obtain the desired picture on all channelswithout having to retune each time a new channel is selected. This isparticularly important where the television receiver'is provided with aremote control system, because the con- Or, the fine tuner may changeautomatically venience with which the viewer can select the channelsfrom a place remote from the receiver is largely'offset if it is.necessaryto manually adjust the fine tuning when a new channel isselected.

The fine tuning control may, also be used. to operate the ultra highfrequency tuner to permit selection of any of the eighty individual UHFchannels. For the tuning system to provide thevarious tuning functionssuch as remote and local VHF channel selection, fine tuning and UHFtuning, and yet be of simple construction to reduce A further object isto provide a television tuner including a channel selector and a finetuner in which the fine tuner has substantially the same tuning rangefor channels of different frequencies. 1

Another object of the present invention is to provide a combined channelselector and fine tuner for television receivers in which the finetuning of each channel may be adjusted and preset independently of theother channels.

A still furtherobject of the invention isto provide'a simple tunerstructure in which a channel selector and preset fine tuner mechanismmay be directly coupled to an ultra high frequency tuning section toprovide continuous tuning of the UHF channels.

Still another object is to provide a motor driven television tuner witha preset mechanism which provides individual channel fine tuning, andwhich may also serve as an indexing device for the motor driven channelselector.

A feature of the invention is the provision of a television tuner of thechannel selector type with wafers for the various tuner sections havingcircuit elements thereon and switch contactsfor selectively connectingthe elements, and with the elements all being on one side of each waferand having terminals extending to the other side and secured together onthe other side as by dip soldering.

Thev elements may include a cylindrical conducting strip at the edgecf awafer forming inductor sectionfor high frequency channels. v I

Another feature of the invention is the provision of a television tunerhaving a channel selector for selecting channels intwo frequency rangeswhich are spaced from each'sother, with a fine tuning device including acoil and a conducting core movable therein which is resonant at afrequency between that utilized in the ranges and which providessubstantiallythe same tuning variety upon movement of the core forchannels in the two frequency ranges. A feature ofthe invention is theprovision of a tuner for television receivers including a channelselector and a fine tuning device having a spring biased element forcontroling its tuning effect, and a rotary cam which causes movement ofthe element to various tuning positions. The cam may include a wheelcoupled to the channel selector andlhaving a plurali'tyof independentlyadjustable members thereon located in positions corresponding to theindividual channels, with arotary device for "adjusting the cam memberscoupled to a fine tuning shaft which is movable both axially androtatably, and'with the adjusting device being brought into engagementwith the cam member corresponding to the selected channel upon axialmovement of the fine tuning shaft and adjusting the cam member by rotarymovement of the shaft. A further feature of the inventionis theprovision of a television tuner including an ultra high frequencysection and a fine tuning section, with a fine tuning shaft movable bothaxially and rotatably, a mechanism disengageably coupling the shafttothe ultrahigh frequency section when the shaft is axially released toprovide continuous tuning of the ultrahigh frequency channels, andanother mechanism disengageably coupling the shaft to the fine tuningsection when the shaft is depressed to provide fine tuning adjustment. l

Another feature is the provision of a motor driven teleing a switch tostop the motor when thechannel selector reaches thedesired position. g

Still another feature is the provision of a motor driven televisiontuning system including a channel selector having a wheel with indexingcams cooperating with an index switch for controlling the motor and withother cams for providing fine tuning control, and including reductiongears coupling the channel selector to the motor, with a Geneva movementgear and a motor switch actuated thereby to coordinate the gear systemwith the index cams and index switch.

The invention is illustrated in the accompanying drawings in which:

FIG. 1 is a perspective view of a television tuner in accordance withthe invention;

FIGS. 2 and 3 are plan views showing the two sides of a wafer of thetuner of FIG. 1;

. FIG. 4 is a cross section view through the wafer along the lines 44 ofFIG. 2;

FIG. 5 is a perspective view of the fine tuning device;

FIG. 6 is an enlarged side view of the fine tuning device;

FIG. 7 is a circuit diagram of the television tuner of the inventionincluding VHF and UHF tuning sections;

FIG. 8 is a plan view, partly in section, of a composite televisiontuner forming one embodiment of the invention, having a VHF channelselector, a preset fine tuning mechanism and a UHF section;

FIG. 9 is an enlarged sectional view taken along lines 9-9 of FIG. 8showing in particular the preset fine tuning mechanism;

FIG. 10 is a sectional view taken along lines 10-10 of FIG. 9 showingparticularly the cam follower and the adjustable cam wheel device of thefine tuning mechamsm;

FIG. 11 is an end view of the embodiment of FIG. 8 taken along lines11--11 showing part of the pulley system for coupling the fine tuningshaft to the UHF section;

FIG. 12 is an elevational view of a motor driven form of the tuner witha cam wheel which provides preset fine tuning and automatic channelselection;

, FIG. 13 is a view of the channel indicator provided in the embodimentof FIG. 12;

FIG. 14 is an end view taken along lines 14-14 of FIG. 12 showing thestructure of the cam wheel;

FIG. 15 is a view taken along lines 15-15 of FIG. 12 showing the motor,and the gear box associated therewith;

FIG. 16 is an enlarged view of the gear box of FIG.

-12 with the cover plate removed to reveal the internal mechanism;

FIG. 17 shows the interlock switch for the Geneva motion;

FIG. 18 is a schematic diagram of the motor driving circuit;

FIG. 19 shows another embodiment of the invention .in which the channelselector shaft and the fine tuning shaft are coaxial;

FIG. 20 is an end view of the embodiment of FIG. 19 showing particularlythe rotary adjusting device and the driving gears therefor;

FIG. 21 is a plan view of an embodiment of the invention in which thecontrol members are disc cams and the fine tuning circuit element is acapacitor;

FIG. 22 is a sectional View taken along line 2222 of FIG. 21 showing inparticular the shape of the disc cams;

and

FIG. 23 is a plan view of a variation of the variable capacitor finetuning mechanism.

are all provided on one side of each wafer with terminals extending tothe other side where they are interconnected as by dip soldering. Thefine tuning device includes a variable circuit component with a movableelement which is positioned by a rotary cam structure. The device may bea coil having distributed capacity to tune the same between the twofrequency ranges which includes the channels to be selected, and aconductor movable in the coil to vary the inductive and capacitiveeffect thereof in the two frequency ranges. The cam structure may be anangularly disposed plate for manual rotation, or a cam wheel having aplurality of cams, such as adjustable screws, carried thereon. The wheelis mounted on and rotates with the channel selector shaft so that thecam corresponding to the selected channel is aligned with the adjustingdevice. A fine tuning shaft, which may be either coaxial with, oroff-set from, the channel selector shaft, is movable axially to engagethe adjusting device with the cam aligned therewith, and is rotatable toturn the adjusting device and preset the engaged cam. A cam follower isengaged by the cam corresponding to the selected channel and controlsthe fine tuning circuit element to establish the desired tuning.

The initial or released position of the axially movable fine tuningshaft may be utilized to provide continuous ultra high frequency tuning.With this arrangement, the fine tuning shaft is effectively coupled tothe preset fine tuner when it is in the depressed position, and theshaft is effectively coupled to the ultra high frequency tuning sectionwhen it is in the released position.

Automatic motor driven channel selection may be provided, and adual-purpose cam wheel may control the fine tuning and also theenergization of the drive motor to stop the motor when the channelselector reaches a predetermined position. This is accomplished byproviding a second set of cams on the cam wheel, selected ones of whichare positioned to actuate an indexing switch in the motor circuit asthey move in succession to the predetermined position. The automatictuning system may involve several functions which are controlled by orare coordinated with the dual-purpose cam wheel.

Referring to FIGS. 1-6 of the drawings, there is shown a televisiontuner 10 including a very high frequency (VHF) section 11 of the rotarychannel selector type, with a fine tuner 12. The VHF section 11 includesa housing 13 and rotary switch wafers 14-17 controlled by a channelselector shaft 18 which extends through the wafers and is journalled inthe housing, and which has an actuating knob 20 positioned on theoutside of the receiver cabinet. A hollow shaft 21, about the shaft 18is the control for fine tuning and is provided with a control knob 22also positioned outside the receiver cabinet.

All of the wafers 14-17 are of the same basic construction shown inFIGS. 2-4, and each has circuit elements such as coils 23 and theconductive strip 24 mounted on one side thereof. The waters include arotary switch element which fits on a flattened portion 19 of theselector shaft 18, and is rotated thereby to selectively connect theelements. The coils are selected by the rotary switch to tune in thelow-range channels (2-6), and various sections of the strips areselected by the switch to tune in the high-range channels (7-13). It maybe noted that the strip 24 is cylindrical and extends around thecircular edge of the wafer, and is mounted perpendicularly with respectto the wafer. Connectors 25 are secured to the switch contacts and haveportions bent to form tubular cavities 25a extending on the oppositeside of the wafer from the coils and strips. The

ends 23a of the coils 23 extend into the cavities 25a as shown in FIG.4, and the extensions 24a of the strip 24 extend into other cavities25a. This construction makes the wafers more compact and permits theelectrical connections to be made by dipping the connectors 25 insolder. The solder rises in the tubular cavities to make a goodelectrical connection between the parts. The insulating wafer body 14protects the circuit elements 23 and 24 during the soldering operation,and mechanical connectors such as eyelets, clips and the like which mayproduce faulty electrical connection are avoided.

of mixer tube 30. from terminal 31 which provides a constantintermediate of the frame includes apertures 55 for receiving theportions 53, and a strut 56 has slots therein for receiving the portions54. The strut 56 is removably supported on a fixed end section 13a and aremovable end section 13b of the frame 13, and the shaft 18 whichextends through the wafers is also supported in bearings provided inthese sections. The side section of the frame 13 forms a chassis andsupports circuit components including the tubes 28 and 39, which areconnected to the circuit elements on the wafers. A shield '7 cooperateswith the frame 13 to provide an enclosing housing about the wafers. Ashield 58 is provided for the antenna input section of the tuner, whichincludes the elements 26 and 27.

The fine tuning device 12 is shown in detail of FIGS. 5, 6 and 10. Thisincludes a coil 33 wound on a tubular insulating form 34, with a coreextending into the form including a supporting rod 35 having a core 42thereon. The core moves in a recess 43 in the form34 to variouspositions with respect to the coil 33. The core- 42 is made of powderediron and its position changes both the inductance and the capacity ofthe coil. The wall of the forrn34 about the recess is very thin so thatthe capacity change produced by movement of the core is quite large. Thecoil form 34has a mounting base 36 connected to the housing 13, and therod 35 extends through the housing. The core is operated by a cam whichin this embodiment is a cam wheel or plate 33 connected to shaft 21 anddisposed angularly with respect to shaft 21. The rod is biased againstthe wheel 38 by a spring 39. The Wheel 38 is supportedon a collar whichis held to the housing 13 by a spring 31. As the shaft 21 is rotated,the part of wheel 38 engaging the rod 35 moves toward and away from thecoil 33 to position the core 42 within the coil. The position of thecore 42 determines the reactance of the coil 33 which changes theeffective reactance of the circuit in which it is connected andtherefore-establishes the line tuning of the television receiver withwhich the tuner is associated. p I

. FIG. 7 is a circuit diagram which shows the circuit of the VHF sectionof the tuner including the fine tuner 12. This also shows an ultra highfrequency section which will be described hereafter. ,The input from theVHF antenna is applied through a filterincluding the coils 26 andthrough a balun 27 which converts the balanced input to a single endedinput. The signal is applied from the balun to the wafer 14, whichoperates to selectively c onnect various sections of the strip 24 andthe coils 23 to provide the required inductance for a selected channel.The selected signal is applied to the cascode amplifier including thetwo sections of tube 2%. The output of the amplifier is applied to thewafer which further selects the signal. The signal is applied throughcoupling section 29 to the grid of mixer tube 30. The grid circuit ofthe mixer is tuned by elements on the wafer 16. The

triode section 39a, which may be included in the same envelope as themixer section 30, is coupled to the wafer 17 to form an oscillator whichapplies'signals to the grid The output of the tuner is derived frequencyoutput. It will be noted that the fine tuner 12 is connected across theinductance of the wafer 17 to provide fine tuning of the oscillator.

The VHF television band includes two space-d frequency ranges. Theoscillator frequency may vary from 100-130 megacycles on the low-rangechannels and from 220 to 259 megacycles on the high-range channels. Thefine tuning device l2 including coil 33 and core 42 is parallel resonantat 140 mc., between the two used ranges, when the core is at itsmid-range position. Above this frequency the unit is capacitive andbelow this frequency it is inductive. Frequency changes are produced inthe high-range channels primarily due to the changein capacitancecreated by the proximity of the core and also by the change in resultantcapacitancewith the varying resonant frequency determined by thechanging core position. On the low range channels, the frequency changeis produced mainly by the inductive change with movement of the core.The fine tuning device provides a wide and relatively uniform finetuning range for all channels.

In FIGS. 8-11 there is shown the tuner 10 including the VHF section 11previously described with the fine tuner 12, combined with a UHF section40. The fine tuning device is of the same construction as describedabove but it is operated in a different way. More particularly theactuator is arranged to be preset for the various VHF channels, and thesetting is combined with the control for the UHF tuner.

Referring particularly to FIGS. 8 and 10, it will be seen thatthe rod355 supporting the core 42 of the fine tuner is engaged by a camfollower provided by rocker 41 which is pivoted at 44. The cam followeror rocker 41 is controlled by a plurality of adjustable control membersor cams 46 which in the embodiment of FIGS. 8-11 are double slottedscrews. There are twelve of these screws 46 mounted in a circular arrayon a cam wheel 47 and spaced angularly to correspond to positions 2-13of the channel selector. The member corresponds to the ultra highfrequency position of the channel selector and is'not adjustable becausetheultra high frequency tuning is independent of the cams, as will beexplained further.

The cam Wheel 4"! has a hub 48 (FIG. 10) through which the channelselector shaft 18 extends. The hub 48 is in the form of a sleevewhich iskeyed to the channel selector shaft 18 so that the wheel 47 rotates withshaft 18 as the channels are selected. The cam screws 46 are spacedangularly about the center of disc47 such that when a channel isselected the corresponding cam screw revolves to the position occupiedby the screw shown in section in FIG. 10. The screws are threadedthrough the wheel 47 and therefore will move axially when rotated. Thewheel 47 has a recessed surface 63 which is engaged by a flange, 62 oneach screw to limit the screws axial movement in one direction, andwheel 47 has a radially projecting lip 64 which is engaged by the flange62 to limit the screws axial movement in the opposite direction. Thetapered end 61 of each screw is engageable with the rocker arm 41, andit may be seen that the axial position of the screws with respect to thewheel 47 determines the position of the rocker arm and thereforecontrols the position of rod 35 and of the core 42 in coil 33 When thechannel selector shaft 18 is r0 tated to change from one channel toanother, a different one of the screws 46 is moved into engagement withrocker'arm 41, thereby changing its position and that of core 42 inaccordance with the setting of the screw.

The screws .46 are preset to provide the desired fine tuning by means ofa rotary adjusting device designated generally at 71. In the embodimentof FIGS. 8ll the device 71 is a screwdriver head including a bladeportion 72 which fits into the slotsin the screws 46. The body portion73 of the screwdriver 71 is rotatably mounted in an arm 76 which extendsbetween the channel selector shaft 18 and the fine tuning shaft 50. Thescrewdriver has a spur gear77 attached thereto which forms part of agear train further including an idler gear 78 which is mountedon the'arm76, and a driving gear 79 secured to the fine tuning shaft 50 androtated thereby. This gear train provides amplification of the rotationof the fine tuning shaftsothat the viewer can tune the coil 33 throughits entire range without releasing the fine tuning axially androtatably. Shaft 50 is biased by a spring 84 to a rest position in whichthe washer 86 abuts against frame 52. When the knob 51 is pushed, thearm 70 is moved toward the cam wheel 47 by the gear 79, thereby movingthe adjusting device 71 into engagement with the screws 46 alignedtherewith. The adjusting device 71 may then be rotated to change thesetting of the engaged screw by rotating the shaft 50 and the gears77-79. When the fine tuning knob 51 is released, the arm 76 and the finetuning shaft 71 are returned to the initial position by the biasingspring 84.

Thus, in order to adjust the fine tuning of the television receiver,theviewer rotates the channel selector knob 20 to the positioncorresponding to the desired channel, and then depresses and rotates thefine tuning knob 51 to engage the adjusting device 71 with the controlmember corresponding to the selected channel. The fine tuning knob 51 isrotated back and forth until the picture appears to be properly tunedand is then released. This operation may be repeated for each channel,and once the channels are fine tuned in this manner they will not haveto be returned unless there is some change in the signal or in thecircuit elements which control the tuning.

The initial or rest position of the fine tuning shaft 50 may be employedto provide continuous tuning of the ultra high frequency channels, aspreviously mentioned. To accomplish this, a disengageable couplingmechanism 91 is connected between the ultra high frequency section 40and the shaft 50. The coupling mechanism 91 includes a pair of crowngears 92-93, and these together with a number of pulleys 94-97 transmitrotary motion of shaft 50 to the ultra high frequency tuning shaft 98.The ultra high frequency section 40 is shown in the circuit diagram ofFIG. 7 and includes variable capacitors 99 which change the tuning in acontinuous manner to select desired UHF channels.

The outer crown gear 93 and the drive pulley 94 are secured to a sleeve101 which is rotatably journaled in the frame 36. The shaft 50 extendsthrough sleeve 101 and is both axially and rotatably movable withrespect to the sleeve. The inner crown gear 92 is secured directly tothe shaft 50, and therefore when this shaft is depressed, the crown gear92 moves away from the crown gear 93 so that shaft 50 is uncoupled fromthe pulleys 94-97. In this depressed position, shaft 50 is coupled tothe fine tuning mechanism by the gears 77-79, the adjusting device 71,and the cam wheel 47 which together constitutes a disengageable couplingmechanism. When shaft 50 is released, the spring 84 returns it'to theinitial position, so that the crown gears 92 and 93 mesh, therebycoupling shaft 50 to the UHF section 40. Rotation of the shaft willrotate sleeve 101 and drive the pulleys 94-97 to control the ultra highfrequency tuning of the receiver. Thus, there are actually twodisengageable coupling mechanisms associated with shaft 50, one for thedepressed position and another for the release position.

The arrangement of the pulleys may be understood by considering FIGS. 8,9 and 11 together. In FIG. 11 it may be seen that the pulleys 94 and 95are coupled together by a cord 90 which is also wound around sleeve 101and certain portions of a pivotal arm 102. Starting from sleeve 101, thecord passes over the end 100 of the arm 102 and then around pin 106.Then the cord passes around pulley 95, around pulley 94 and back aroundpulley 95. The cord continues around the pin 107, over the other end 99of the arm 102 and back to sleeve 101. The arm 102 is pivoted on acentral pin 103 which is connected to the frame 52. The pivotal movementof the arm 102 is limited by a stop portion 104 extending therefromthrough an opening 105 in the frame 52. The arm is constructed of amaterial which presents relatively small friction to the cord so thatthe cord can slide over the ends and pins thereon.

Starting in the condition where the arm is in the position illustratedin FIG. 11, if the shaft 50, sleeve 101,

63 and pulley 94 are rotated clockwise, the initial movement of the cordwill pivot the arm 102 clockwise until the stop portion 104 abuts oneside of the opening through which it extends. When the arm reaches thisposition, the cord will slide over the ends 99 and 100 and the pins 106and 107 of the arm 102 to provide high speed direct drive for the pulley95. Pulley 95 is on the same shaft as pulley 96, and the latter iscoupled by a timing belt 110 to pulley 97 which rotates the UHF tuningshaft 98.

When the desired channel is approximately tuned in, the shaft 50 andsleeve 101 may be rotated backwards in the counter clockwise directionin order to fine tune this channel. As sleeve 101 rotates counterclockwise, the cord pivots the arm 102 back to the initial position, andduring this pivotal movement of the arm, the pulley moves slowly becauseof the relatively small movement of the pins 106 and 107 around whichthe cord extends. Thus, the pivotal arm 102 is a change-speed devicewhich permits high speed rough tuning and then on reverse rotation ineither direction, low speed fine tuning of the UHF channels.

As previously stated, the UHF tuner is shown in the circuit of FIG. 7.Signals from the UHF antenna are coupled to a first resonant line 103which is tuned by two of the capacitors 99. A second resonant line 104,tuned by the remaining two of the capacitors 99, controls the frequencyof an oscillator including the tube 105. The received signals from line103 are mixed with the oscillations from line 104 in crystal detector108 to provide a difference frequency. The output of the detector, whichis a fixed intermediate frequency, is applied to the UHF position ontuner wafer 14. This signal is amplified in the cascode amplifierincluding the tube 28 and in the mixer 30. The local oscillator 30a isinoperative so that the mixer 30 produces the same frequency at output31 as for VHF operation. The wafer 17 includes contacts for selectivelyapplying 13-]- to the oscilltaor tube when the channel selector isswitched to the VHF position.

FIGS. 12-17 illustrate another embodiment of the invention whichprovides both preset fine tuning and automatic channel selection. Theparts in FIGS. 12-17 which have corresponding parts are designated bythe same reference numerals as in the prior figures. In the embodimentof FIGS. 12-17 the channel selector shaft 18 is driven by a motor 111which is coupled to the shaft by a gear train enclosed in the gear box112. The shaft 18 does not extend outside the cabinet wall representedby the fragmentary wall portion 113. On the end of shaft 18 there is achannel indicator projecting disc 114 (see FIG. 13). Numberscorresponding to the VHF channels are blanked out of the disc 114, andthese numbers are arranged peripherally on the disc so that they may berevolved successively into alignment with a small projection screen 116provided behind an opening in the front cabinet wall 113. A source oflight is provided by the apertured enclosure 117 and the bulb 119. Thus,as a given channel is selected, light forming the corresponding numberwill be projected onto the screen 116 The screen may be of frosted glassso that the number will be visible to the viewer.

The preset mechanism including the cam wheel is mounted on the end ofthe selector shaft 18 which extends toward the back of the receivercabinet. The preset fine tuning mechanism functions essentially the sameas that described in connection with FIGS. 8-11. The main structuraldifference is that the rotary adjusting device 17 is driven directly bythe fine tuning shaft 120 with no coupling gears being provided betweenthe shaft and the screwdriver. The shaft 120 is accessible from the rearof the cabinet.

The face of the cam wheel 115 is shown in FIG. 14. From this view it maybe seen that wheel 115 has an inner set of cam screws 46 which providethe preset fine tuning, and an outer set of cam screws 121 which controlthe motor 111 to provide automatic channel selection. A second camfollower 122 is positioned in the path of the cam screws 1 21, and thiscam follower is a rocker arm which actuates an indexing switch 123connected in the control circuit of the motor 111. Those of the camscrews 121 corresponding to the channels which are to be selectedautomatically are screwed into a position where they will engage theactuator 122 and operate switch 123. The rest of the cam screws 121'corresponding to unused channels will be screwed out to a position wherethey will pass rocker arm 122. The screws 121are set by means of anadjusting device 124 with a shaft 125 which is accessible from the rearof the cabinet, and this operates in the same manner as the fine tuningshaft 129.

When the motor 111 is started, either by means of a local switch or aremote control unit, it rotates the selector s switch 141 to open it,and this avoidspossible binding of the pin and wheel as a result ofmanual adjustment of the selector shaft 18. The circuit diagram shown inFIG. 18 facilitates an understanding of the operation of the motorcircuit. Switch 1511 is the main on-oif switch of the receiver. Thisswitch is connected in parallel with the switch 129 which provideson-off operation at a predetermined position of the tuner 10. The motor111 which operates the tuner maybe energized through the circuitincludingpushbutton switch 151 provided on. the receiver. After themotor is energized I through this circuit, operation or" the motor willclose shaft 18 and the cam wheel 115, thereby moving the next The'camwheel 115 may also be provided with a cam I which will shut the receiveroff when the wheel reaches a predetermined position. This cam may belocated at the UHF position of wheel 115, and will engage the switch 129as shown in FIG. 14. Switch 129 controls the supply of power to thereceiver itself, but does not affect the remote control system whichmaybe provided to operate the motor 111. Other switches may be associatedwith cam follower 122 to provide picture blanking and sound muting asthe channels change, as illustrated in FIG. 5.

FIGS. 15 and 16 together with FIG. 12 illustrate the coordination of themotor and reduction gears with the cam wheel 47. The motor 111 is of thedeclutching type and has a rotor 131 which is pulled axially into themotor body 111 when the windings 132 are energized. The rotor 131 is ona shaft which has an extension projecting through the gear box 112 andterminating in a pin 135 which actuates an interlock switch 133. Switch133 is normally open, and when the rotor 131 is pulled in, the interlockswitch is closed. This switch is in series with the index switch 123,and its function is to permit manual adjustment of the channel selectorshaft 18. Every time the camwheel 115 is rotatedso that one of the cams121 is disengaged from the actuator 122, the indexswitch 123 closes.Unless the interlock switch is open, this would drive the channelselector to the next cam. The interlock switch is always open when themotor 111 is de-energized as is the case when theshaft 18 is operatedmanually. Whenever the motor is energized, switch 133 will be closed,and closing of the index will cause the motor to drive the channel,selector to .the next position.

FIG. 16 shows the gear train which couples themotor 111 to the channelselector shaft 13. The gear train includes a gear cluster 136 whoseouter teeth mesh with a pinion 127 on the motor shaft 130, and whoseinner teeth mesh with aspur gear 137. The spur gear has a 141 on theoutsideof the gear box which has an actuator 140 extending into the gearbox in the path of the pin 138 (see FIG. 17). The switch 141 isconnected in parallel with the interlock switch 133 and the index switch123, and is normally closed. Thus, the motor will only stop when the pin138 engages the actuator of switch 133. As the tuner moves away from aset channel the switch 123 will close so that a holding circuit isprovided through these two switches to cause continued motor operationuntil the tuner reaches a set channel to open the switch 123 andde-energize the motor. The switch 141 coupled to the Geneva motion is inparallel with switches 123 and 133 to prevent stopping of the motorexcept when the Geneva motion is at a set position.

A remote control system 152 (FIG. 18) may be provided in the receiverhaving a relay with contacts 153. The contacts 153 are in parallel withthe pushbutton contacts 151 to start the tuning operation by energizingthe motor 110. Accordingly the motor tuning operation can be startedeither by remote operation or by operation of the pushbutton 151 at thereceiver. It is obvious that either of thesefacilities may be providedor both may be provided if desired.

Another embodiment of the channel selector and tuner in accordance withthe invention is illustrated in FIGS. 19 and 20. The construction issimilar in many respects to that previously described so only thesignificant distinctions will be described in detail. Only afragmentaryportion of the tuner is illustrated because it will be apparent that theremaining parts may be provided in vac cordance with the previousdescription. In this embodimerit, the channel selector shaft 118 extendsthrough and is coaxial with the fine tuning shaft 128. The line tuningshaft 123 is rotatable about shaft-118 and is also axially movable withrespect thereto. Shaft 128 is urged to a restposition by the spring 184.The rotary adjusting device -171 is rotatably mounted on the arm 176which has a collar portion 183 Within spring 184 and through which theselector shaft 118 extends. One end of'the fine tuning shaft 128 abutsagainst the arm 176 so that when this shaft is moved axially, it pushesthe arm 176 and moves the rotary adjusting device 171 into,

engagement with the cam screw aligned therewith. The cam screws 146arecarried in a circular array on the cam wheel 147 which is mounted onthe channel selector shaft by means on a hub 148 in the same manner asdescribed in connection with FIGS. 1-4. The screws 146 have cup-shapedheads with a serrated edge which grips the resilient end portion 172 ofthe adjusting device 171. A support bracket 190 is secured to the frame150 and provides additional support for the adjusting device 171 whilepermitting it torotate and move axially The body portion 1730f theadjusting device has a spur gear 177 attached thereto which meshes withthe driving gear 179 secured to the fine tuning shaft 128. Thus, theline tuning shaft 128 is depressed axially to engagethe adjusting device171 with the control member 146 aligned therewith, and is then rotatedto adjust the axial position of the control member. The gears 177 and179 speed up the rotation of the device compared to the fine tuningshaft to facilitate setting up the fine, tuning as previously explained.

The coil 33, the coil form .34, the core 35 and the rocker arm 41 areall provided in accordance with the previous description, and theiroperation is the same as previously described.

The embodiment of FIGS. 21 and22 is a modification of the embodiment ofFIGS. 19 and 20, and therefore the same reference numeralsare applied tolike parts. The

1 1 main differences are that the variable circuit element whichprovides the fine tuning is a capacitor consisting of a fixed plate 201and a movable plate 202. The latter is controlled by a pivotal rockerarm 203 having a cam follower roller 204 cooperating with disc cams 205.

The disc cams have body portions which extend through the cam wheel 147and have cup-shaped heads 206 on the other side of the wheel. The teeth207 on the cups 206 mesh with teeth 208 on the rotary adjusting device209. The arrangement of the gears 117 and 179, the arm 173 and spring184 is in accordance with the description of FIGS. 9 and 10.

The disc cams 205 have a heart shape and are arranged circularly on thewheel 147 so that the disc corresponding to the selected channel engagesthe cam follower roller 204, and positions the rocker arm 203 andcapacitor plate 202. When shaft 118 is rotated to select a differentchannel, a different disc cam is brought into engagement with the camroller 204 and moves arm 203 and capacitor plate 202 to a new position.The discs 205 are adjusted by depressing shaft 128 to engage the rotaryadjusting device 299 With the head 206 of the cam aligned therewith, andby rotating shaft 123 until the desired picture is obtained. It may benoted that the adjustable cams 206 do not move axially, but rather areadjusted to a desired angular position to control the rocker arm 203.

The embodiment of FIG. 23 is a modification of the embodiment of FIGS.19 and 20, and illustrates a fine tuning device which does not have aseparate cam follower member such as the rocker arms 38, 138, and 203described in connection with the other embodiments. Only part of themechanism is shown since this serve to illustrate the modifiedconstruction. The fine tuning circuit element is a book-type capacitorincluding a fixed plate 211 and a movable plate 212 with a cam follower213 provided directly on the plate 212. The follower 213 is moved as thescrews 146 (only one is shown) are rotated into engagement therewith bythe channel selector shaft 118. The fine tuning shaft 128 is coaxialwith shaft 118 and is both rotatable and axially movable to control therotary adjusting device 171 as previously described.

It is apparent from the foregoing description that the tuning system ofthe invention is of economical construction and is capable of providingvarious types of tuning. The basic VHF television tuner may be combinedwith UHF tuning and may be either manual or motor driven for remotecontrol. Fine tuning is provided which may be preset to control eachchannel independently of the others through operation of a cam wheelwhich controls a single variable circuit element. The cam wheel may alsocontrol the motor of an automatic tuning system if this is desired. Thefine tuning shaft may drive the ultra high frequency tuner, and this isaccomplished without interfering with the fine tuning settingsf The finetuning device provides a wide tuning variation for all the VHF channels.

' We claim:

1. In a television receiver, a tuning system including in combination,motor driven channel selector means having a rotatable selector shaft, awheel mounted on said selector shaft and rotatable thereby, said wheelhaving a plurality of fine tuning cams mounted thereon in a circle aboutsaid selector shaft, and said wheel having a plurality of indexing camsmounted thereon in another circle about said selector shaft, first andsecond cam followers supported respectively in the rotational paths ofsaid fine tuning cams and said indexing cams and movable thereby, finetuning circuit means controlled by said first cam followers to establishdesired fine tuning settings according to the position of said selectorshaft, and control circuit means including an index switch actuated bysaid second cam follower for controlling the operation of said motordriven channel selector means.

' 2. In a television receiver, a tuning system including in combination,channel selector means having a rotary selector shaft, fine tuningcircuit means including a movable element, a first cam followerassociated with said movable element of said fine tuning circuit meansfor moving the same to establish desired fine tuning settings, a motorfor rotating said selector shaft, a control circuit for said motorincluding means for energizing said motor, an index switch connected insaid control circuit for con trolling the operation of said motor, asecond cam follower associated with said index switch for actuating thesame, means supporting said first and second cam followers in apredetermined spaced relation, a wheel coupled to said channel selectorshaft and positioned adjacent said first and second cam followers, firstand second sets of independently adjustable cams with each set includingcams corresponding to the channels selected by said channel selectormeans, said first and second sets of cams each being mounted on saidwheel in a circular array, with the cams in said first set thereof beingengageable with said first cam follower and said cams in said second setthereof being engageable with said second cam follower, first adjustingmeans having a portion positioned opposite said first set of cams,second adjusting means having a portion positioned opposite said secondset of cams, and first and second actuating means respectivelyassociated with said first and second adjusting means for engaging thesame with the cam aligned therewith to permit adjustment of the cams todesired settings.

3. In a television receiver, a tuning system including in combination,channel selector means having a rotatable selector shaft, a wheelmounted on said selector shaft and rotatable thereby, said wheel havinga plurality of index ing cams mounted thereon in a circle about saidselector shaft, a cam follower supported in the rotational path of saidindexing cams and movable thereby, a motor for rotating said selectorshaft, gear means coupling said motor to said selector shaft, said gearmeans including a Geneva wheel, and driving wheel with rotary memberthereon which meshes with said Geneva wheel during a portion of eachrotation thereof, control circuit means for starting and stopping saidmotor including first and second switches connected in parallel so thatsaid motor stops only when both of said switches are open, said firstswitch being opened by said cam follower upon engagement thereof withsaid cams, and said second switch being opened by said rotary member ata point in the rotation of said driving wheel where said rotary memberis disengaged from said Geneva wheel.

4. In a television receiver, a switch type tuning system including incombination, motor driven channel selector means having a rotatableselector shaft, reactance means for fine tuning of each selectedchannel, support means carried by said selector shaft and having aplurality of axially adjustable cam screws mounted in parallel relationwith said selector shaft, a portion of said cam screws being positionedto individually control said reactance means for fine tuning purposes,an energizing circuit for said motor driven channel selector meansincluding a switch positioned adjacent said support means, anotherportion of said cam screws individually engaging said switch in oneaxial position thereof for opening said switch and de-energizing saidmotor driven channel selector means, and rotatable adjustment meansmovable into engagement with each of said cam screws for axiallypositioning the same to provide fine tuning and programming forautomatic selection of desired channels.

5; In a television receiver, a tuning system including in combination,motor driven channel selector means having a rotatable selector shaftand means for detenting said selector means, reactance means for finetuning of each selected channel, support means carried by said selectorshaft and having a plurality of screw members axially adjustable on saidsupport means, a portion of said screw members being positioned toindividually adjust said reactance means for fine tuning purposes, anenergizing circuit for the motor of said motor driven channel selectormeans including switch means to open said circuit, means driven by saidmotor to open said switch means in successive detent positions of saidselector shaft, another portion of said screw members individuallyengaging said switch means in one axial position thereof foropening saidswitch and de-energizing said motor, and manually rotatable meansmovable into en- References Cited in the file of this patent UNITEDSTATES PATENTS Cady Oct. 11, 1960 Kemeny Dec. 6, 1960 Cross et a1. Feb.27, 1962

1. IN A TELEVISION RECEIVER, A TUNING SYSTEM INCLUDING IN COMBINATION,MOTOR DRIVEN CHANNEL SELECTOR MEANS HAVING A ROTATABLE SELECTOR SHAFT, AWHEEL MOUNTED ON SAID SELECTOR SHAFT AND ROTATABLE THEREBY, SAID WHEELHAVING A PLURALITY OF FINE TUNING CAMS MOUNTED THEREON IN A CIRCLE ABOUTSAID SELECTOR SHAFT, AND SAID WHEEL HAVING A PLURALITY OF INDEXING CAMSMOUNTED THEREON IN ANOTHER CIRCLE ABOUT SAID SELECTOR SHAFT, FIRST ANDSECOND CAM FOLLOWERS SUPPORTED RESPECTIVELY IN THE ROTATIONAL PATHS OFSAID FINE TUNING CAMS AND SAID INDEXING CAMS AND MOVABLE THEREBY, FINETUNING CIRCUIT MEANS CONTROLLED BY SAID FIRST CAM FOLLOWERS TO ESTABLISHDESIRED FINE TUNING SETTINGS ACCORDING TO THE POSITION OF SAID SELECTORSHAFT, AND CONTROL CIRCUIT MEANS INCLUDING AN INDEX SWITCH ACTUATED BYSAID SECOND CAM FOLLOWER FOR CONTROLLING THE OPERATION OF SAID MOTORDRIVEN CHANNEL SELECTOR MEANS.